Home Inspection State Practice Exam 2026 - Free Home Inspection Practice Questions and Study Guide

The least effect on the deflection of a dimension lumber floor system is attributed to the width of the joist. While joist width does play a role in overall structural capacity, the factors that primarily influence deflection include the spacing between joists, the length of the joist, and the type of lumber used.

Joist spacing impacts how weight is distributed across the floor system; closer spacing leads to less deflection. The length of the joist is crucial as longer joists will naturally deflect more under a load compared to shorter ones. The type of lumber has a significant impact as different species and grades have varying strengths and stiffness characteristics, which directly affect their ability to resist deflection.

On the other hand, joist width primarily contributes to the overall load-bearing capabilities rather than being a direct factor in deflection. A wider joist can support more weight, but its width alone does not significantly change how much it will bend or deflect under that weight compared to the other factors mentioned. Thus, choosing joist width as the choice with the least effect on deflection is a valid conclusion.